|256-1||Actinobacteria-Escovopsis interactions in the higher attine ant agriculture|
|Autores:||Lucas Andrade Meirelles (UNESP - São Paulo State University - Campus Rio Claro) ; Fernando Carlos Pagnocca (UNESP - São Paulo State University - Campus Rio Claro) ; Odair Correa Bueno (UNESP - São Paulo State University - Campus Rio Claro) ; André Rodrigues (UNESP - São Paulo State University - Campus Rio Claro) |
Attine ants maintain an association with actinobacteria in the genus Pseudonocardia found in the microbial biofilms on the integument of workers. It is thought that these bacteria help the ants in the defense against pathogens through the secretion of antimicrobial substances. Two theories have been proposed to explain the interactions between Pseudonocardia and the microfungal garden parasite Escovopsis: one supports co-evolution between these organisms and the other supports parallel evolution. Here, we evaluate the interactions of actinobacteria and Escovopsis in the higher attine ant agriculture. Twelve strains of Pseudonocardia isolated from Trachymyrmex (a higher attine ant) were tested against three Escovopsis strains. One strain was isolated from Trachymyrmex (a non-leafcutter ant) and two strains were isolated from Atta and Acromyrmex (leafcutter ants). The Escovopsis mycelial growth (in cm²) was measured in the presence and absence (control) of the bacteria. Six replicates were made for each actinobacteria-Escovopsis combination and differences in the mycelial growth were evaluated using two-way ANOVA. Our results showed that all Pseudonocardia strains inhibited Escovopsis, but the inhibition rates were variable among the actinobacteria strains (p< 0.05). In addition, differences in the mycelial growth inhibition among the three tested Escovopsis strains were observed. Specifically, growth inhibition of Escovopsis isolated from Trachymyrmex and Acromyrmex were not significantly different (p= 0.831). On the other hand, the Escovopsis strain isolated from Atta was inhibited by all actinobacteria strains in a lesser extent when compared with the remaining Escovopsis strains, and this result was significantly different (p< 0.05). Overall, our findings suggest that Pseudonocardia strains isolated from Trachymyrmex possibly secrete antimicrobial substances which are effective against Escovopsis from other attine ant genera. Due to the few studies about Pseudonocardia from Trachymyrmex, additional research is needed to evaluate more thoroughly the apparent absence of specificity here demonstrated.
Palavras-chave: antagonism, Attini, defense, fungiculture, symbionts